After watching the program and reviewing the training guide, you will gain knowledge and understanding of the various fastening devices and assembly methods used in manufacturing. For more information, download the full training guide.

Mechanical Fastening

The most common mechanical fastening methods include:

• Integral fasteners 
• Threaded fasteners
• Non-threaded fasteners
• Stapling

Integral fasteners are formed areas designed into sheet metal products. Integral fasteners function by interlocking or interfering one component with other components during assembly. The three most common types of integral fasteners include:

• Embossed Protrusions: Are formed between two sheet metal components by drawing a small cup-shaped section through them. As the metals are squeezed through the components they impact and expand on a die, producing an interlocked button with a greater diameter than the drawn section. This process is also called clinching or clinch joining.
• Edge Seams: Interlock the edges of sheet metal parts by folding the edges of both components over each other. Edge seams not only reinforce the entire assembly but also eliminate sharp edges.
• Hemming: Assembles sheet metal parts together by bending the edge of one component more than 180 degrees over the edge of another sheet metal component.

Threaded fasteners are a low-cost means of mechanically joining and holding parts together. They are used where subsequent disassembly and reassembly may be required. Threaded fasteners include machine screws, nuts, and bolts.

Non-threaded fasteners include:

• Rivets: Rivets are one piece, permanent mechanical fasteners inserted through matching holes in component parts. 
• Pins: Pins are simple, low-cost mechanical fasteners. Once installed, they can function as locking devices, locating elements, pivots, and bearing faces. Pins may be tapered or straight, with a head or without. Two common pins types include:
  • Clevis Pins: Clevis pins have a drilled hole at one end to receive a cotter pin or a spring-wire pin. Clevis pins are primarily used as pivots and linkages.
  • Dowel Pins: Dowel pins are used to align mating parts in precise position.
• Washers: Washers are primarily used as bolt and screw seats to help distribute loads and stresses. They are installed in assemblies which are subject to shock and vibration. 

Adhesive Bonding

Adhesive bonding forms permanent joints that cannot be disassembled without destroying components. Adhesive bonding can be defined as molecular cohesion between unlike liquids or solids that resists interfacial separation. The advantages with respect to the use of adhesive bonding include:

• Part stresses are uniformly distributed over a large surface.
• Similar and dissimilar materials can be joined
• Thick and thin parts not suitable for mechanical fastening or welding may be bonded
• Joints can be sealed from intrusive atmospheres and substances
• The weight of an assembly can be significantly reduced 
• Costs are much less than with other fastening methods

Automated Assembly

Assembly can represent one of the highest direct labor costs in manufacturing. These costs can be significantly reduced through automation. To realize these savings, the parts being assembled must be designed to avoid shingling or overlapping. The three major automated assembly machine configurations include:

• Dial, or rotary, index machine: Dial, or rotary, index machines have workstations and tooling mounted around the periphery of the indexing table or on a central column. This type of machine is usually limited to smaller size work of minimum complexity.
• In-line indexing assembly machine: In-line indexing assembly machine move the components to be assembled in an oval, square, or rectangular path around the periphery of the machine. The circumferential machine type is the most common in-line indexing assembly machine.
• Carousel assembly machine: The carousel machine consists of a series of fixtures attached to a chain or belt which moves the components from one work station to another along a horizontal plane.

The selection of any automated process machine is dependent upon many factors, including:

• Production rate requirements
• Size and weight of parts to be assembled
• Number of automated operations involved
• The need for additional manual operations
• The complexity of assembly operations to be performed